In rheumatoid arthritis (RA), synovial inflammation results in focal erosion of articular bone. Despite treatment attenuating inflammation, repair of erosions with adequate formation of new bone is uncommon in RA, suggesting that bone formation may be compromised at these sites. Dynamic bone histomorphometry was used in a murine model of RA to determine the impact of inflammation on osteoblast ...

Osteoblast differentiation of mesenchymal stem cells is regulated by both soluble factor (e.g., bone morphogenetic proteins (BMP)) and mechanically transduced signaling, but the mechanisms have only been partially elucidated. In this study, physical association of BMP Receptor I (BMPRI) with integrin β1 sub-unit (Iβ1) was hypothesized to mediate osteoblast differentiation of rat bone marrow-der...

PPAR gamma is activated by diverse ligands and regulates the differentiation of many cell types. Based on evidence that activation of PPAR gamma 2 by rosiglitazone stimulates adipogenesis and inhibits osteoblastogenesis in U-33/gamma 2 cells, a model mesenchymal progenitor of adipocytes and osteoblasts, we postulated that the increase in marrow fat and the decrease in osteoblast number that occ...

Osteoporosis is one of the most common diseases and can be treated by either anti-resorption drugs, anabolic drugs, or both. To search for anabolic drug targets for osteoporosis therapy, it is crucial to understand the biology of bone forming cells, osteoblasts, in terms of their proliferation, differentiation, and function. Here we found that protein palmitoylation participates in signaling pa...

ERRα is an orphan member of the nuclear receptor family, the complete inactivation of which confers resistance to bone loss induced by ageing and estrogen withdrawal to female mice in correlation with increased bone formation in vivo. Furthermore ERRα negatively regulates the commitment of mesenchymal cells to the osteoblast lineage ex vivo as well as later steps of osteoblast maturation. We se...

BACKGROUND p38 MAPK activity plays an important role in several steps of the osteoblast lineage progression through activation of osteoblast-specific transcription factors and it is also essential for the acquisition of the osteoblast phenotype in early development. Although reports indicate p38 signalling plays a role in early skeletal development, its specific contributions to adult bone remo...

MicroRNAs (miRNAs) are a family of small, non-coding RNAs (17-24 nucleotides), which regulate gene expression either by the degradation of the target mRNAs or inhibiting the translation of genes. Recent studies have indicated that miRNA plays an important role in regulating osteoblast differentiation. In this study, we identified miR-203 and miR-320b as important miRNAs modulating osteoblast di...

The heterotrimeric G protein subunit Gsα stimulates cAMP-dependent signaling downstream of G protein-coupled receptors. In this study, we set out to determine the role of Gsα signaling in cells of the early osteoblast lineage in vivo by conditionally deleting Gsα from osterix-expressing cells. This led to severe osteoporosis with fractures at birth, a phenotype that was found to be the conseque...

Evans, Jodi F., James K. Yeh, and John F. Aloia. Osteoblast-like cells of the hypophysectomized rat: a model of aberrant osteoblast development. Am J Physiol Endocrinol Metab 278: E832–E838, 2000.—In a previous work, we demonstrated that the osteoprogenitors derived from the marrow stroma of the hypophysectomized (HX) rat demonstrate enhanced proliferative and differentiation capacities when pl...

Exogenous bone morphogenetic proteins (Bmp) are well known to induce ectopic bone formation, but the physiological effect of Bmp signaling on normal bone is not completely understood. By deleting the receptor Bmpr1a in osteoblast lineage cells with Dmp1-Cre, we observed a dramatic increase in trabecular bone mass in postnatal mice, which was due to a marked increase in osteoblast number that wa...